Intervertebral disc nucleus implants and methods

• US 6,893,466 B2
• Filed: 09/24/2002
• Issued: 05/17/2005
• Est. Priority Date: 08/30/2000
• Status: Expired due to Term

• Current Assignee: SDGI Holdings Incorporated (Medtronic Plc)
• Original Assignee: SDGI Holdings Incorporated (Medtronic Plc)
• Inventors: Trieu, Hai H.
• Primary Examiner(s): STEWART, ALVIN J
• Application Number:
  US10/253,453
• Publication Number:
  US 20030023311A1
• Time in Patent Office: 966 Days
• Field of Search: 623 1711- 1716
• US Class Current: 623/17.16
• CPC Class Codes: A61B 2017/0256 for the spine
• CPC Class Codes: A61F 2/30965 Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping
• CPC Class Codes: A61F 2/441 made of inflatable pockets or chambers filled with fluid, e.g. with hydrogel
• CPC Class Codes: A61F 2/442 Intervertebral or spinal discs, e.g. resilient non-disc-shaped intervertebral inflatable pockets A61F2/441; non-disc-shaped intervertebral fusion implants A61F2/4455
• CPC Class Codes: A61F 2/4611 of spinal prostheses
• CPC Class Codes: A61F 2002/2817 Bone stimulation by chemical reactions or by osteogenic or biological products for enhancing ossification, e.g. by bone morphogenetic or morphogenic proteins [BMP] or by transforming growth factors [TGF]
• CPC Class Codes: A61F 2002/30062 (bio)absorbable, biodegradable, bioerodable, (bio)resorbable, resorptive
• CPC Class Codes: A61F 2002/30092 using shape memory or superelastic materials, e.g. nitinol
• CPC Class Codes: A61F 2002/30133 kidney-shaped or bean-shaped
• CPC Class Codes: A61F 2002/30179 X-shaped
• CPC Class Codes: A61F 2002/302 toroidal, e.g. rings
• CPC Class Codes: A61F 2002/30224 cylindrical
• CPC Class Codes: A61F 2002/30291 spirally-coiled, i.e. having a 2D spiral cross-section
• CPC Class Codes: A61F 2002/30563 having elastic means or damping means, different from springs, e.g. including an elastomeric core or shock absorbers
• CPC Class Codes: A61F 2002/30594 slotted, e.g. radial or meridian slot ending in a polar aperture, non-polar slots, horizontal or arcuate slots
• CPC Class Codes: A61F 2002/30604 modular
• CPC Class Codes: A61F 2002/30677 Means for introducing or releasing pharmaceutical products, e.g. antibiotics, into the body
• CPC Class Codes: A61F 2002/30838 Microstructures
• CPC Class Codes: A61F 2002/30891 Plurality of protrusions
• CPC Class Codes: A61F 2002/30906 shot- sand- or grit-blasted
• CPC Class Codes: A61F 2002/30909 : Nets
• CPC Class Codes: A61F 2002/30925 : etched
• CPC Class Codes: A61F 2002/30957 : using a positive or a negative model, e.g. moulds
• CPC Class Codes: A61F 2002/4415 : elements of the prosthesis being arranged in a chain like manner
• CPC Class Codes: A61F 2002/444 : for replacing the nucleus pulposus
• CPC Class Codes: A61F 2002/4495 : having a fabric structure, e.g. made from wires or fibres
• CPC Class Codes: A61F 2002/4627 : with linear motion along or rotating motion about the instrument axis or the implantation direction, e.g. telescopic, along a guiding rod, screwing inside the instrument
• CPC Class Codes: A61F 2210/0004 : bioabsorbable
• CPC Class Codes: A61F 2210/0014 : using shape memory or superelastic materials, e.g. nitinol
• CPC Class Codes: A61F 2230/0015 : Kidney-shaped, e.g. bean-shaped
• CPC Class Codes: A61F 2230/0058 : X-shaped
• CPC Class Codes: A61F 2230/0065 : toroidal, e.g. ring-shaped, doughnut-shaped
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2230/0091 : helically-coiled or spirally-coiled, i.e. having a 2-D spiral cross-section

Abstract

Nucleus pulposus implants that are resistant to migration in and/or expulsion from an intervertebral disc space are provided. In one form of the invention, an implant includes a load bearing elastic body surrounded in the disc space by an anchoring, preferably resorbable, outer shell. In certain forms of the invention, the elastic body is surrounded by a supporting member, such as a band or jacket, and the supporting member is surrounded by the outer shell. Kits for forming such implants are also provided. In another form of the invention, an implant is provided that has locking features and optional shape memory characteristics. In yet another aspect of the invention, nucleus pulposus implants are provided that have shape memory characteristics and are configured to allow short-term manual, or other deformation without permanent deformation, cracks, tears, breakage or other damage. Methods of forming and implanting the implants are also described.

Claims

1. An intervertebral disc nucleus pulposus implant, comprising:

(a) a load bearing elastic body positioned in an intervertebral disc space; and

(b) a resorbable material partially or completely surrounding said load bearing elastic body and partially or substantially filling the remaining intervertebral disc nucleus space;

wherein said resorbable material is uncured when introduced into the intervertebral disc space and thereafter cures after introduction into the intervertebral disc nucleus space.

2. The implant of claim 1, wherein said resorbable material is elastic after curing.

3. The implant of claim 1, wherein said resorbable material comprises a material selected from the group consisting of fibrin, albumin, gelatin, collagen, elastin, silk, demineralized bone matrix, polyethylene oxide, polyethylene glycol, polyvinyl alcohol, polypropylene fumarate and combinations thereof.

4. The implant of claim 1, wherein said elastic body is comprised of a hydrogel material.

5. The implant of claim 4, further including a pharmacological agent associated with said hydrogel material, said resorbable material, or a combination thereof, said agent selected from the group consisting of growth factors, anti-inflammatory drugs, antibiotics, analgesics, and combinations thereof.

6. The implant of claim 5, wherein said pharmacological agent is a growth factor.

7. The implant of claim 6, wherein said growth factor is selected from the group consisting of transforming growth factor β

, bone morphogenetic proteins, fibroblast growth factors, platelet-derived growth factors, insulin-like growth factors and combinations thereof.

8. The implant of claim 7, wherein said growth factor is a recombinant human protein.

9. The implant of claim 4 wherein said hydrogel is a member selected from the group consisting of natural hydrogels, hydrogels formed from polyvinyl alcohol, acrylamides, polyacrylic acid, poly(acrylonitrile-acrylic acid), polyurethanes, polyethylene glycol, poly(N-vinyl-2-pyrrolidone), acrylates, poly(2-hydroxy ethyl methacrylate), copolymers of acrylates with N-vinyl pyrrolidone, N-vinyl lactams, acrylamide, polyurethanes and polyacrylonitrile.

10. The implant of claim 1, wherein said elastic body is comprised of a polymer selected from the group consisting of elastomers and hydrogels.

11. The implant of claim 1, wherein the outer surface of said elastic body includes projections extending therefrom, said projections configured for enhancing fixation of said body in said intervertebral space.

12. The implant of claim 1, wherein the outer surface of said elastic body is microtexturized.

13. The implant of claim 12, wherein said microtexturizing is performed by a process selected from the group consisting of bead blasting, plasma etching, chemical etching and combinations thereof.

14. The implant of claim 1, wherein the outer surface of said elastic body includes reactive chemical groups selected from the group consisting of hydroxyl groups, amino groups, carboxyl groups and organofunctional silane groups, said groups enhancing fixation of said elastic body to said resorbable shell.

15. The implant of claim 1 wherein said resorbable material is a tissue sealant or an adhesive.

16. The implant of claim 15 wherein said tissue sealant or adhesive is made from a material selected from the group consisting of fibrin, albumin, gelatin, collagen, elastin, silk, demineralized bone matrix, polyethylene oxide, polyethylene glycol, polyvinyl alcohol, polypropylene fumarate and combinations thereof.

17. The implant of claim 1 wherein said elastic body comprises a load bearing elastic body sized for placement in an intervertebral disc space, said body having a first end, a second end, a central portion, and a first configuration wherein said first end and said second end are positioned adjacent to said central portion to form at least one inner fold, said elastic body configurable into a second, straightened configuration for insertion through an opening in an intervertebral disc annulus fibrosis, said body configurable back into said first configuration after said insertion;

wherein said body provides an implant having a substantially solid center when the body is in its first configuration.

18. The implant of claim 17 wherein said elastomer is selected from the group consisting of silicone, polyurethane, copolymers of silicone and polyurethane, polyolefins, nitrile and combinations thereof.

19. The implant of claim 1 wherein said elastic body comprises a load bearing elastic body having shape memory and sized for placement into an intervertebral disc space, said body having a first end, a second end, and a central portion;

wherein said shape memory biases said body to a first configuration wherein said first end and said second end are positioned adjacent to said central portion to form at least one inner fold and to provide a substantially solid center core when the implant is in its first configuration;

said elastic body configurable into a second, straightened configuration for insertion through an opening in an intervertebral disc annulus fibrosis;

wherein said shape memory returns said body to said first configuration after said insertion;

wherein said elastic body has a surface that includes wrinkles, indents or projections that relieve stress and prevent cracking or tearing of the implant when the implant is straightened for implantation.

20. The implant of claim 1 wherein said cured resorbable material anchors the implant in place to prevent migration in or from the disc space.

21. The implant of claim 1 wherein said cured resorbable material seals a defect in the annulus surrounding the intervertebral disc nucleus space.

22. The implant of claim 1 wherein said cured resorbable material compensates for the differences in geometry and size between the disc space and the implant.

23. The implant of claim 1 wherein said cured resorbable material is replaced by tissue after being resorbed.

24. The implant of claim 1 wherein said implant is wide enough to support adjacent vertebrae, and is of a height sufficient to separate adjacent vertebrae.

25. The implant of claim 1 wherein said implant has a volume of at least about 70% of the volume of the disc space.

26. The implant of claim 1 wherein said implant has a volume of at least about 90% of the volume of the disc space.

27. The implant of claim 1 wherein said hydrogel is a crosslinked hydrogel.

28. The implant of claim 1 wherein said elastic body comprises a hydrophilic polymer.

29. The implant of claim 1, wherein said elastic body comprises a member selected from the group consisting of silicone, polyurethane, copolymers of silicone and polyurethane, polyolefins, neoprene, nitrile, vulcanized rubber and combinations thereof.

30. The implant of claim 29 wherein said polyurethane is a member selected from the group consisting of thermoplastic polyurethanes, aliphatic polyurethanes, segmented polyurethanes, hydrophilic polyurethanes, polyether-urethane, polycarbonate-urethane and silicone polyether-urethane.

31. The implant of claim 1, wherein said elastic body comprises a member selected from the group consisting of glucomannan gel, hyaluronic acid, polysaccharides, cross-linked carboxyl-containing polysaccharides, and combinations thereof.

32. The implant of claim 1 wherein said elastic body has a compressive strength of between about 0.1 Mpa and about 20 Mpa.